Automatic telephone register and method



3, 1935. c.1. mm 2,010,868

AUTOMATIC TELEPHONE REGISTER AND METHOD Filed Sept. 8, 1952 4 Sheets-Sheet 1 HIS A'rns Au 13, 1935. c. I. LAITTIG 2,010,868

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Aug. 13, 1935. c. l. LATTlG AUTOMATIC TELEPHONE REGISTER AND METHOD Filed Sept. 8, 1952 4 Sheets-Sheet 5 mw 6E mR 6E Patented Aug. 13, 1 935- UNITED STATES PATENT OFFICE 2,010,868 AUTOMATIC TELEPHONE REGISTER AND METHOD My present invention relates to automatic telephone exchange systems and it has for its object to provide means for recording certain data which is often desired for either temporary or permanent record.

More specifically my invention has for its object the provision of instrumentalities for recording the numbers of telephone lines on which incoming calls originate, or the recording of the numbers of called telephone lines, or the numbers of both the calling and called lines when a connection is established. As a further adjunct I also provide means for including in the record the date on which the connection between any two lines in a telephone system is efiected with further information as to the length of the time during which the telephone exchange apparatus was in service.

In further contemplation of my invention have devised a method to be used in conjunction with the recorded calls to enable the data collected to be used by a telephone company, in its auditing and billing departments whereby the compiling of the usual monthly telephone bills will be greatly facilitated, An important object of my invention is to increase the accuracy of the tabulating work required for billing purposes and particularly in making up the charges rendered to subscribers for calls in excess of their minimum allotment and those for which additional charges are made for overtime use of the system and where fixed tariffs are established.

In accordance with the foregoing my invention further contemplates making a permanent photographic record of the data, wh ch is automatically set up upon the initiation of a call, this phase of the invention comprehending as a further step condifioning the apparatus upon the response of the called subscriber, the exposure of the sensitizedsurface, its advancement to a new position, and the return of the indicating apparatus to its normal position upon the disconnection occurring simultaneously with the release of the central office switches upon abandoment of the call.

To these and other ends my invention comprises further improvements, arrangement of parts and advantages all as will be more fully described in the accompanying specification, the novel features being set forth in the appended claims.

In the drawings:

Fig. l is aschemat c illustration of a recording mechanism for automatic telephone systems showing one embodiment of my invention.

Fig. 2 is a front view of the assembled recording mechanism with the casing removed the parts being shown as they appear looking toward the right on the section line 2 --2 of Fig. 3.

Fig. 3 is a vertical sectional view taken on the line 3 -3 of Fig. 2.

Fig. 4 is a vertical sectional view taken on, the 5 line 4 4 of Fig. 2.

Fig. 5 is a side elevation of a digit indicator and its operating device.

Figs. 5A and 5B are views showing elevations of the right and left hand ends of the digit oper- 10 ating device.

Figs. 6, 6A, 6B are similar views, respectively of the sequence switch and its operating device by means of which certain digit indicators are operatedsuccessively.

Fig. 6C is a cross section on the line 6 -6 of Fig. 6.

Fig. '7 is a view showing a portion of a photographic record after development.

Fig. 8 is a view showing a portion of a record sheet compiled from data such as illustrated in Fig. 7 as it appears when made up for billing purposes.

Fig. 9 is an enlarged face view of a digit indicator.

Fig. 10 is a detail view of the exposure window showing the several indicators as they appear behind the exposure lamp and in front of the sensitized surface.

Similar reference characters in the several figures indicate similar parts.

, In illustrating my invention I have not deemed it necessary to show the layout of a complete automatic telephone exchange system and the numerous switches employed for effecting interconnection between two subscribers lines as such are well known to telephone engineers and others skilled in the art. My invention is applicable to any automatic telephone system whether the central oflice switching mechanism be that 01 the panel type or the so-called Strowger system using step-by-step switches having both vertical and rotary movement but as the last mentioned system is used in many of the larger telephone exchanges. of the country and comprises by far the 4 greater number of such installations in present day use I have shown this type of apparatus as exemplary in describing one form of apparatus, by which my invention may be carried out. v Typical telephone exchange circuits used with the Strowger automatic switches are shown.

In Fig. 1, I have indicated generally an incoming calling telephone line A and an outgoing called, or wanted telephone line B which are placed in intercommunication through the instrumentalities oi finder, selector and connector switches C, D and E respectively which are arranged in groups according to the number of lines to be served.

For the purpose of simplification in the description of the invention the telephone exchange system diagrammatically illustrated is assumed to be one having 1000 subscribers. The thousand lines are all connected to the finder switches of which there are 10 groups each containing 100 lines the terminals of which are connected in multiple and appear on the banks of said switches so that when a call is originated on any line one of the finder switches allocated to the particular group in which said line appears is automatically operated to pick up or connect its wipers with the terminals of said line and extend the latter to the brushes or wipers of an idle selector switch. At this point the calling subscriber dispatches a group of impulses by manipulation of his dialing device A. These impulses operate the selector D and establish or set up the hundreds digit of the .called line. The selector switch wipers come to rest upon terminals of a link circuit leading to an idle connector switch E. Thereupon the calling subscriber dispatches a second group of impulses which are indicative of the tens digit of the called line and causes its switch shaft to be moved vertically and a third group of impulses,

representing the units digit of the called line, to

cause the switch shaft to rotate and come to rest with its wipers in contact with the terminals of the wanted line B.

In connection with the finder switch C, which is one of a group of ten such switches in the exchange system adopted for illustrative purposes, I have illustrated the lower end of the switch shaft C and shown a pair of ofi normal contacts C which are open when the switch is in its normal or idle position and which automatically close upon the first step of said switch. I have also illustrated the usual control magnets of this switch known as the vertical magnet V, the rotary magnet R and the release magnet L on each of which I provide a set of normally open contacts v, r and Z. The circuits controlled by the contacts 12, r are utilized to actuate the digit indicators of the calling line and the circuit controlled by the contacts I subsequently releases said indicators as will be further described. v

At the central ofiice I also provide means for successively operating the hundreds, tens and units indicators of the called line as the calling subscriber dials the different groups of impulses. In this particular mechanism I make use of the quick and slow relay combinationnow in universal use on all two wire automatic telephone systems and described in United States patent to C. L. Goodrum issued May 18, 1926, No. 1,585,024, entitled Controlling mechanism for progressively movable electric switches and other devices. This digit controller comprising a rapidly responsive relay I, and two relays 2 and 3 both of which are slower in their releasing action. The relay I is in series with one side of the line circuit connecting the finder C and the connector D has the usual non-inductive winding and also has an armature IA which vibrates with each impulse dialed. On its forward movement the armature completes a circuit through magnet 2 causing it to become energized and in turn to attract its armature 2A. On its back stroke the armature fice for all. For the purpose or illustration I have shown a simple arrangement of parts comprising a vertically movable ratchet bar 20 carrying at its upper end an indicator strip 2| provided with numerals from 0 to 9. This strip I form in a suitable manner whereby the indicia are in light transmitting areas for photographic purposes. If desired the strip may be made of thin metal and the indicating character stencil cut therein as shown in Fig. 9, or a transparent or translucent strip may be used and the portions surrounding the outline of the numerals darkened.

The means employed for operating each indicator cosists of an electro magnet, the series of suchmagnets shown in Fig. 1 being indicated by 22, 23, 24, 25 and 26. The armature 21 of the magnet carries a pawl 28 which is impelled forwardly by a spring 29 against a retainer 30, in its normal position, and moves into contact with the teeth on the bar 20 when actuated for the purpose of elevating the bar step by step. In practice I mount the several indicators side by side as shown in Fig. 2 and so'arrange them that their positions of adjustment may be recorded photographically. To this end I provide a long narrow window 3| extending horizontally as shown in Fig. 10, having a series of openings for the several digit indicators already described and others to be further mentioned. At one side of the indicators in rear of the window, I mount a strip of photographically sensitized material 32 which may be either paper or film,

. and at the other side is an exposure lamp 33.

Provision is made for flashing the lamp upon disconnection of a successful charge call and for advancing the film after such recording exposure.

I have previously mentioned the manner in which the finder switches are grouped and as they are assigned to a given number of subscribers lines this fact simplifies the recording of numbers of calling lines by making provision for recording the group number in conjunction with the tens and units digits of such line. Hence in one of the window openings I permanently fix an index character such as the numeral 7, in Fig. 10 indicating the seventh group. To the left of this point are two other openings in which I arrange adjustable strips by means of which the month and the days of the month are indicated. For smaller telephone exchanges these strips may be manually adjustable although it will of course be understood that they can be operated automatically by a clock mechanism.

Referring now to Fig. 1 it will be observed that the magnet 22 which operates the tens digit indicator is in a circuit 22A which is closed successively by armature 1) upon each impulse received by the vertical magnet V to advance the tens digit indicator one step for each vertical step of the switch shaft C. Likewise the magnet 23 has a circuit 23A which receives an impulse of current through the armature r for each impulse of current received by the rotary magnet R. Therefore assuming the calling line terminals appear in the seventh group of finder switches and that the calling line is number 38 then the figures. 3 and 8 appear in the window 3| following the group figure 7.

The indicators which set up the number of the wanted or called party are those controlled by magnets 24, 25 and 2t. Magnet 24 has a circuit A .leading to the first contact 3 of the sequence switch, the magnets 25 and I. are connected by individual circuits 25A and 25A to the second and third contacts 253 and "B respectively of said switch.

armature 3A. The wiper 50 of this switch is connected by wire 50A to the forward contact of armature 2A. when the finder extended the callin'g line to the connectorswitch, the telephone line being closed at the switch hook contacts, the control relays i and 2 were simultaneously energized. Now upon the subscriber dispatching the first group of impulses the first dial movement opens the line momentarily which releases armature iA which then closes the following circuit; ground, armature IA and its back contact, ar-

mature 2A and its forward contact, conductor 50A, switch wiper 50, contactllB, wire 14A, magnet 24 to battery. The simultaneous action of relay 3 acting in unison with the first pulse closes the circuit for the sequence switch-F, .as follows:

ground, armature 3A and its .forward contact, conductor 55A, magnet 55 to battery but as this circuit remains energized by reason of the slow deenergizing characteristics of relay 3 the magnet 24 receives the full number of impulses dialed in unison with the movement of the selector switch D. Upon cessation of this group of impulses the armature'3A is released and spring 5 advances the wiper 50 into contact with terminal 253 to direct the second group'of dialing impulses to indicator magnet 25. Similarly the magnet 26 is energized upon the subscriber dispatching the third group of impulses by the engagement of wiper 50 with contact 253.

From the foregoing it will be readily seen that the hundreds, tens and units digits (in a 1000 line exchange and others in a larger exchange) are separately operated in consonance with the movements of the selector and connector switches in response to the calling subscribers acts in performing the necessary dialing operations. In

Fig. the numerals 9, 5 and 6 indicate the number of the line called.

Imaddition' to the foregoing, I also provid means for indicating the elapsed time aconnection is maintained between two subscribers lines or during which telephone service is being rendered. This device is indicated by G and is somewhat similar to the instrumentalities already described. but it is operated periodically to record arbitrary units of time which may be either minutes or subdivisions thereof. The operating magnet 60 of the elapsed time indicator is in the circuit comprising the conductor 50A leading to the malse contact 50B of an armature 500 on a relay 8| included in circuit with the rapid or pulsing relay i. Relay 5! is provided with a non-inductive winding and is polarized so that it does not pull up or become energized until the. usual reversal of current occurs upon the answering of the called party. The armature, NC is connected to a brush 50D on a rotating commutator 52, driven in any suitable manner, and

arranged to interrupt thecircuit to magnet 60 periodically.

The juxtaposition of all of the indicators in parallel relationship makes it possible to employ a single release device H for tripping them. In

' FiB. 1, this element comprises a magnet I5 having the circuit NA which is closed by the oil normal contacts C of the finder switch upon its first step. The armature ll of this magnet is normally retracted by a spring 12 and these parts eil'ect movements in opposite directions of a common operating member HA, shown in the form of a bar in Fig. 1. when the armature is attracted it causes all of the locking pawls 13 of the several digit indicators, the time indicator and the sequence switch to engage their respective ratchets and as the magnet 10 remains en- 'ergized while the finder switch is occupied with a connection it follows that all of the parts which are operated pursuant to establishing a connection remain in their respective positions of adjustment until the finder switch is released and returns to its normal position.

Recording of the adjusted or operated position of the several indicators in accordance with my invention may be accomplished photographic-ally and to this end the means I have devised, consists in mounting in a light tight chamber, formed by the casing 15 in. which the whole mechanism is enclosed, a movable sensitized surface, heretofore designated as 32, which may be of sufilcient length to record all calls occurring during a day period. If a photographic paper or film is used it may be in the form of a supply roll 80 from which it is rewound onto a receiving spool 8i after passing around the guide rolls 82, I3 and a stationary guide by means of which it is held adjacent the rear sides of the indicator strips in alinement with the window 3|. On one end of the upper guide roll 83, I provide a ratchet 83A and bearing against said roll is a presser roll 833 which will insure the intermittent movement of said paper or film. Cooperating with the ratchet is a pawl 84 carried by an armature 84B and retracted by a spring A. The magnet for actuating the armature is indicated by 85. In front of the window 3| is the exposure lamp 33 which is completely enclosed by the enlargement 15A of the casing.

The recording apparatus is not operated in the event the called party does not respond but if the ing, in conjunction with the time indicator, a

pair of normally open spring contacts 86 and 81 which close upon the first movement of the time indicator. The contacts 85 I include in the circuit of the lamp 33 which may be traced as follows: battery conductor 33A, lamp 33, conductor 333, contacts 86, conductor 33C to contacts I on the finder switch release magnet. As contacts 1 remain open until the release magnet L 'is enere gized to restore the switch to normal thelamp is not'lighted until the release of the finder switch is accomplished. The film operating magnet is in a circuit leading from the battery and comprises a conductor l85A which is closed to ground through the contacts 81 which are closed by reason of the movement of the time indicator.

the opening of thecircuit of the common release magnet 10, and by the dropping of the time indicator the spring 84A acts to step the film forward to position an unexposed portion thereo in alinement with the window 3 I.

Periodically the film or paper roll will be removed and the used or exposed portion developed. The record thereon will appear as indicated in Fig. 7. If the sensitized developed surface is on paper the record may be severed crosswise in strips and all of those relating to a given subscriber collated and preferably pasted on a card in the order of their dates. Such a card will in accordance with my invention have provision for such other data, as shown in Fig. 8, as may be' desired to facilitate the work of the billing department of a telephone company in tabuiating or computing the charges to be rendered on the longitudinally each of said devices being actuated independently in succession in unison with the step by step movements of said switch in contacting with the terminals of said line, and means for permanently recording the set position of said strips.

2. In an automatic telephone system comprising line finder switches means for recording the numbers of the lines on which incoming calls are originated comprising separate indicating devices for the tens and units digits of such numbers associated with a group of finder switches and automatically operated independently in unison with such a switch as it is successively actuated to find the terminals of a calling line and means for permanently recording the adjusted position of said indicators.

3. In an automatic telephone system comprising a line finder switch, means for recording the number of a line on which an incoming call is originated comprising a tens indicator and a separate units indicator, separate means for correspondingly operating said indicators as the switch operates to select the tens group and the unit terminals of an incoming telephone line and means for recording the adjusted position of said indicators.

4. In an automatic telephone exchange system comprising line finder switches divided into a plurality of groups, means for recording the numbers of the lines on which calls originate comprising a master indicator for each group of finder switches, and tens and units digit indicators for each of such groups arranged to be controlled by the several finders therein and operated in unison therewith as the corresponding terminals of the calling line are selected and means for recording the switch group indicator and the adjusted position of the digit indicators.

5. In an automatic telephone system, the combination with a line finder switch capable of automatically selecting any one of a plurality of incoming lines on which a call ma originate, of a plurality of separate indicator tuated seriatim in accordance with the movement of the switch to indicate the digits ofthe line so connected and means for recording the adjusted position of said indicators.

The time indicator circuit is disrupted, following 6. The combination with a plurality of sub scribers telephone lines. a central oflice line finder switching mechanism capable of automatically selecting the terminals of one of such lines on which a call originates, of a set of indito select the tens group in which an incoming line is placed and a rotary movement to select the unit terminals of such line, an indicator for the tens digits actuated vertically in unison with the vertical stepping movement of the switch, another indicator for units digits actuated vertically in unison with the rotary movement of the switch and means for recording the position of adjustment of said separate indicators upon the completion of the operation of said finder switch.

8. A telephone number recording mechanism for telephone exchanges in which connections are established between calling and called subscribers lines by automatic switches including a finder switch which automatically hunts the terminals of a line on which a call originates, said mechanism comprising a master indicator corresponding to the finder switch and plurality of separate digit indicators and means for setting them in unison successively with the operation of the finder switch in selecting the trunk of the calling line to indicate the number of the calling line and means for recording the position of said indicators upon response of the called subscriber.

9. A telephone number recording mechanism for telephone exchanges in which connections are established between calling and called subscribers lines by automatic switches including a finder switch which automatically hunts the terminals of a line on which a call originates, said mechanism comprising a plurality of digit indicators and means for setting them in unison with the operation of the finder switch to indicate the number of the calling line and means for photographically recording the position of said indicators comprising a sensitized surface positioned at one side of the indicators and a normally inoperative light source located at the opposite side thereof arranged to be rendered operative upon response of the called subscriber.

10. The combination with an automatic telephone system comprising subscribers lines and line finder, selector and connector switches for efiecting connections between calling and called lines, of a mechanism for recording the numbers of the lines on which calls are originated, comprising digit indicators and means for operating them automatically in consonance with the movement of the finder in picking up the terminals of such a line, a photographically sensitized surface and an exposure lamp positioned with respect to said indicators to record their position of adjustment and a circuit for lighting the lamp rendered operative upon the response of the called party.

11. The combination with an automatic telephone system comprising subscribers lines and circuit for the lamp both actuated upon the reof the lines on which calls are originated, comprising digit indicators and means for operating them automatically in consonance with the movement of the finder in picking up the terminals of such a line, a photographically sensitized surface and an exposure lamp positioned with respect to said indicators to record their positions of adjustment and a circuit for lighting the lamp rendered operative upon the response of the called party, and energized upon the disconnection of the calling subscribers line.

12. The combination with an automatic tele-- phone system comprising subscribers lines and line finder, selector and connector switches for efiecting connections between calling and called lines, said switches also operating to release automatically upon the termination of a call, of a mechanism for recording the numbers of the lines on which calls are originated, comprising digit indicators and means for operating them automatically in consonance with the movement of the finder in picking up the terminals of such a line, a photographic sensitized surface and an exposure lamp positioned with respect to said indicators to record their positions of adjustment and a circuit for. lighting the lamp rendered operative upon the response of the called party, and energized upon the release of the finder switch.

13. In an automatic telephone exchange system having switching means for automatically connecting a calling subscribers line with a desired called subscribers line embodying a finder for picking up the terminals of a line on which a call originates and a connector for completing the connection, the combination with a plurality of digit indicators and means for operating them separately in unison with the operation of the finder switch, of photographic means for recording the adjusted positions of said indicators rendered operative upon the answering of the called subscriber and actuated upon the restoration of the switch system to its normal position.

14. In an automatic telephone system having switching means for automatically connecting a calling subscribers line with a desired called subscribers line embodying a finder for picking up the terminals of a line on which a call originates and a connector switch for completing the connection, the combination with a plurality of. digit indicators and means for operating them separately in unison with the operation of the finder switch, of photographic means for recording the adjusted positions of said indicators comprising a strip of photographic sensitized material and an exposure lamp positioned with respect to said indicators, means for advancing the sensitized material and a circuit for the lamp both rendered operative upon the answering of the called line and actuated upon the restoration of the switch system.

15. In an automatic telephone exchange system having switching means for automatically connecting a calling subscribers line with a desired called subscribers line embodying a finder for picking up the terminals of a line on which a call originates and a connector switch for completing the connection, the combination with a plurality of digit indicators having light transmitting areas corresponding to the several digits and means for operating the indicators in consonance with the operation of the finder switch, of a photographic sensitized surface at one side of the indicators and a lamp at the other side thereof, means for advancing said surface and a turn of the finder switch to its normal position.

16. In an automatic telephone exchange system having switching means for automatically connecting a calling subscribers line with a desired called subscribers line embodying a finder for picking up the terminals of a lineon which a call originates and a connector switch for completing the connections, said switches being arranged to serve a plurality of telephone lines, the combination with an indicator common to the finder switches, a plurality of digit indicators individual to said finder switches and means for operating them in consonance with the movement of one or another of said finders in picking up the terminals of a line on which a call is originated to indicate the number of said line served by such switches, and means for photographically recording the digit indicators in their adjusted positions together with the group indicator. 1

17. In an automatic telephone exchange system having switching means for automatically connecting a calling subscribers line with a desired called subscribers line embodying a finder for picking up the terminals of a line on which a call originates and a connector for completing the connections, said switches being arranged to serve a plurality of telephone lines, the combination with an indicator common to the finder switches, a plurality of digit indicators individual to said finder switches and means for operating them in consonance with the movement of one or another of said finders in picking up the terminals of a line on which a call is originated to indicate the number of said line in the switch group, said indicators comprising light transmitting areas, corresponding to the several digits, a strip of photographic sensitized material and an exposure lamp located at opposite sides of the indicators, means for advancing the sensitized strip and a circuit for the lamp, both rendered operative upon the answering of the called party and each actuated upon the release of the finder switch resulting from the disconnection of the calling subscribers line.

18. In an automatic telephone exchange system having switching means for automatically connecting a calling subscribers line with a desired called subscribers line embodying a finder for picking up the terminals of a line on which a call originates and a connector for completing the connection, the combination with a plurality of digit indicators comprising strips having light transmitting areas, and electromagnets for advancing them step .by step having separate circuits arranged to be energized in unison with the tens and units movements respectively of the finder during its hunting the terminals of a calling line, means for locking the indicators in their adjusted positions which is rendered operative upon the initial movement of the finder and released to restore the indicators to their normal position upon the release of the finder by the abandoning of the subscribers call, a strip of photographic sensitized material and an exposure lamp located at opposite sides of said indicator strips and means for lighting the lamp to record the adjusted positions of said indicators.

19. In'an automatic telephone exchange system comprising subscribers lines having impulse transmitters and central oifice switching devices for efiecting interconnection between a calling line and a called line, the combination with means for recording the numbers of called subscribers lines comprising a plurality of separate digit indicators, for indicating the number of 2. called subscribers line, and an elapsed time indicator movable progressively, of means for operating the digit indicators successively in response to the impulses dispatched by a calling subscriber in setting up the connection, separate means for operating the time indicator during the period connection is maintained between two lines and means for recording the adjusted position of all of said indicators simultaneously upon the termination of the established connection.

20. In an automatic telephone exchange system comprising subscribers lines equipped with impulse dialing devices and central oifice switching mechanism for effecting connection between calling and called lines, the combination with a plurality of digit indicators, for indicating the number of called subscribers line, ofmeans for operating them successively in response to the impulses dialed by a calling subscriber, aprogressively movable indicator for showing the time elapsing during which a connection is established between said lines, means for actuating it rendered operative upon the answering of the called subscriber and means for simultaneously recording the adjusted positionsof all of said indicators which is rendered efiective upon the answering of the called subscriber.

21. In an automatic telephone exchange system comprising subscribers lines equipped with impulse dialing devices and central oifice finder, selector and connector switches, the combination with a plurality of digit indicators for setting up the number of a called subscribers line, of means for operating them successively in consonance with the selective movements of the selector and connector switches, a progressively movable indicator for showing the time elapsing during which an established connector between two lines is in operation, means for actuating it rendered operative upon the answering of the called subscriber, means for simultaneously recording the adjusted positions of all of said indicators rendered eiTective upon the answering of the called subscriber and actuated upon the release of the finder switch.

22. In an automatic telephone exchange system comprising subscribers lines equipped with impulse dialing devices and central office finder,

selector and connector switches, the combination nates and means for operating them successively.

upon the movement of the finder switch, of other digit indicators and means for operating them in consonance with the dialing operations by which the selector and connector switches are operated to set up the number of the called subscribers line, and means for photographically recording the adjusted positions of all of said indicators which is rendered effective upon the answering of the called subscriber and actuated upon the release of the established connection.

23. In an automatic telephone exchange system comprising subscribers lines equipped with impulse dialing devices and central oflice finder, selector and connector switches, the combination with a plurality of digit indicators for setting up the number of a line on which a call originates and means for operating them successively upon the movement of the finder switch, of other digit indicators and means for operating them in consonance with the dialing operations by which the selector and connector switches are operated to set up-the number of the called subscribers line, a separate indicator for showing the elapsed time and means for operating it actuated upon the answering of the called party and continuing during the operation of the connected lines, and means for photographically recording the adjusted position of all of said indicators which is placed in condition for operation upon the answering of the called subscriber and actuated upon the release of the finder switch.

24. In an automatic telephone" exchange system comprising subscribers lines equipped with impulse dialing devices and central oflice finder, selector and connector switches, the combination with a plurality of digit indicators for setting up the number of a line on which a call originates and means for operating them successively upon the movement of the finder switch, of other digit indicators and means for operating them in consonance with the dialing operations by which the selector and connector switches are operated to set up the number of the called subscribers line, a separate indicator for showing the elapsed time and means for operating it actuated upon the answering of the called party and continuing during the operation of the connected lines, said indicators each having light transmitting areas carrying suitable indicia, a photographically sensitized surface and a printing lamp located at opposite sides of the indicators, a circuit for the lamp and means for advancing said surface step by step both conditioned for operation upon the answering of the called subscriber and actuated upon the release of the established connection.

25. In an automatic telephone exchange system comprising subscribers lines equipped with impulse dialing devices and central office finder, selector and connector switches, the combination with a plurality of digit indicators for setting up the number of a line on which a call originates and other digit indicators for setting up the number of the called subscribers line, separate electromagnetic devices for operating the first mentioned indicators automatically in unison with the finder switch inhunting the terminals of a calling line and for operating the second mentioned set of indicators successively in consonance with the group impulses dialed for the operation of the selector and connector switches, means for holding the indicators in their operated positions actuated upon the first movement of the finder switch and released to permit the indicators to return to their normal positions upon the release of said finder switch and photographic means for recording the adjusted positions of all of said indicators.

26. In an automatic telephone exchange system comprising subscribers lines equipped with impulse dialing devices and central oifice finder, selector and connector switches, the combination with a plurality of digit indicators for setting up the number of a line on which a call originates and other digit indicators for setting up the number of the called subscribers line, separate electromagnetic devices for operating the first mentioned indicators automatically in unison with the finder switch hunting the terminals of a calling line and for operating the second mentioned set of indicators successively in consonance with the group impulses dialed for the operation of the selector and connector switches, an elapsed time indicator and means for initiating its recording movement upon the answering of the called subscriber, means for holding all of said indicators in their operated positions against retrograde movement 15 which is actuated upon the first movement imparted to the finder switch and released upon the release of the finder switch to permit the indicators to return to their normal position, and photographic means for recording the'adjusted positions of said indicators comprising a sensitized surface and a recording lamp arranged relatively to said indicators, means for advancing said surface and lighting the lamp upon the termination of a completed call between two subscribers and upon the restoration of the central oflice switches.

27. In an automatic telephone exchange system comprising subscribers lines provided with impulse dialing mechanisms and central ofiice switches, of a plurality of digit indicators, electromagnetic means for operating them individually, to indicate a called telephone number, each of said means having a separate circuit, an indicator sequence switch for progressively selecting said circuits, means for progressively operating said switch upon the termination of each group of impulses dispatched by a calling subscribers dialing mechanism and means for recording the adjusted position of said indicators.

28. The method of compiling billing records for subscribers of automatic telephone exchanges consisting in photographing on a photographical- 1y sensitized surface the positions of adjustable indicators operated in consonance with the movements of central oflice switches showing the numbers of calling and called subscribers lines between which connections are effected developing said surface and collating the data photographed thereon with reference to the lines on which calls have been initiated.

29. The method of compiling billing records for subscribers of automatic telephone exchanges consisting in photographing on a photographically sensitized surface the positions of adjustable indicators operated in consonance with the movements of central ofiice switches showing the numbers of calling and called subscribers lines between which connections are effected together with the elapsed time the connection is maintained, developing said surface, collating the data photographed thereon with reference to the lines originating calls and subsequently computing the charges.

CHARLES I. LATIIG. 

